Self-assembling Peptides

拟议研究计划的目标：该研究计划的总体目标是开发多功能，可注射的水凝胶，该水凝胶对酶的存在动态响应，用于控制治疗分子的释放。特别感兴趣的是肽、蛋白质和DNA的控制释放。******导致纳米纤维形成的基本机制尚未明确阐明（RADA）4。先前的研究（PNAS, 2005, 102(24):8414 8419）表明，肽自组装成微米长的纳米纤维，从小球，发生在60秒内；一个似乎无法用物理解释的时间框架。关于n端氨基酸的添加，我们已经观察到（在制备过程中）氨基酸的化学性质及其随后的水合状态会极大地影响这个组装过程。现在这两种成分已经被确定为纳米纤维形成的关键，进一步的工作将集中在阐明改变实际氨基酸化学组成的影响，以了解单个成分在自组装过程中的作用。此外，为了使这些系统应用于受控药物输送，我们之前的工作表明，n端氨基酸可以用来特异性地修改这些高度水合的水凝胶中不同水类型的种群大小：非冷冻结合、冷冻结合、无界自由。尽管研究人员努力了解溶液中理想肽域的酶活性（生物材料，2011,32(5):1301-1310），但在复杂水凝胶结构中研究酶活性的工作很少，其中纳米纤维的存在、水的类型和区域粘度可能会影响酶的表观活性。这些主题将在本补助金中进一步概述。******这项工作对一个或多个领域的新颖性和预期意义：预计这项工作将为理解涉及RADA4纳米纤维自组装的物理化学方面提供一个框架，并有希望提出解释这些分子快速组装的机制。将这些水凝胶中的水结构和区域粘度联系起来，可以更好地理解纳米纤维化学对酶的移动性和活性的影响。虽然一些工作已经研究了酶作为水的功能，但在水凝胶领域理解这一点对于进一步了解酶在复杂介质中的作用的生物物理学意义至关重要。

Objectives of the proposed research program: The overall objective of this research program is to develop multifunctional, injectable, hydrogels that are dynamically responsive to the presence of enzymes for the express purpose of controlling the release of therapeutic molecules. Of particular interest is the controlled release of peptides, proteins, and DNA. ******The fundamental mechanisms leading to nanofiber formation have not been clearly elucidated for this (RADA)4. Previous work (PNAS, 2005, 102(24):8414 8419) has shown that peptide self-assembly into micron long nanofibers, from globules, occurs within 60 seconds; a time frame that seems to defy a physical explanation. With respects to the addition of N-terminal amino acids, we have observed (in preparation) that amino acid chemistry, and their subsequent hydration state, can greatly affect this assembly process. Now that these two components have been identified as being crucial to nanofiber formation, further work will focus on elucidating the effect of altering the actual amino acid chemical makeup to understand the role individual components have on self-assembly process. Furthermore, in order for these systems to be applied for controlled drug delivery, our previous work has shown that N-terminal amino acids can be used to specifically modify the population size of different water types within these highly hydrated hydrogels: non-freezing bound, freezing bound, unbounded free. Despite efforts understanding the enzymatic activity toward idealized peptide domains in solution (Biomaterials, 2011, 32(5): 1301-1310) little to no work has been conducted on investigating enzymatic activity within the complex hydrogel structure, where the presence of the nanofiber, as well as types of waters, and regional viscosity may affect the apparent activity of enzymes. These topics will be further outlined within this grant.******Novelty and expected significance of the work to a field or fields: It is expected that this work will provide a framework for understanding the physicochemical aspects involved in the self-assembly of RADA4 nanofibers, hopefully presenting a mechanism that explains the rapid assembly of these molecules. Correlating water structures and regional viscosity in these hydrogels should allow for a better understanding of the effect nanofiber chemistry has on the mobility and activity of enzymes. Although some work has investigated enzyme action as a function of waters, understanding this in the realm of a hydrogel will be crucial to furthering a biophysical understanding of enzyme action in complex media.